Characterization of a New S8 serine Protease from Marine Sedimentary Photobacterium sp. A5-7 and the Function of Its Protease-Associated Domain.
Characterization of a New S8 serine Protease from Marine Sedimentary Photobacterium sp. A5-7 and the Function of Its Protease-Associated Domain.
复制标题
海洋沉积发光杆菌属新 S8 丝氨酸蛋白酶的表征。
DOI：
10.3389/fmicb.2016.02016
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发表时间：
2016
影响因子：
5.2
通讯作者：
Chen XL
中科院分区：
文献类型：
--
作者：
Li HJ;Tang BL;Shao X;Liu BX;Zheng XY;Han XX;Li PY;Zhang XY;Song XY;Chen XL
细菌胞外蛋白酶在细菌营养和海洋沉积物有机氮降解中具有重要作用。然而，只有少数蛋白酶从海洋沉积细菌的特点。一些枯草杆菌酶具有插入催化结构域中的蛋白酶相关（PA）结构域。虽然结构分析和缺失突变表明枯草杆菌酶中的PA结构域参与底物结合，但支持这一功能的直接证据仍然缺乏。本文对从海洋沉积物中分离的发光杆菌A5-7分泌的一种蛋白酶P5 -7进行了研究。P57能水解酪蛋白、明胶和胶原蛋白。在40°C和pH 8.0下显示出最高活性。P57是一种新的枯草杆菌酶，与最接近的蛋白酶具有63%的序列同一性。成熟的P57含有催化结构域和插入的PA结构域。结果表明，重组的P57 PA结构域具有与胶原蛋白结合的能力，其中Phe 349和Tyr 432是PA结构域中与胶原蛋白结合的关键残基。本研究首次提供了枯草杆菌酶PA结构域结合底物的直接证据，为进一步了解海洋沉积物中枯草杆菌酶和细菌胞外蛋白酶PA结构域的功能提供了依据。
Bacterial extracellular proteases are important for bacterial nutrition and marine sedimentary organic nitrogen degradation. However, only a few proteases from marine sedimentary bacteria have been characterized. Some subtilases have a protease-associated (PA) domain inserted in the catalytic domain. Although structural analysis and deletion mutation suggests that the PA domain in subtilases is involved in substrate binding, direct evidence to support this function is still absent. Here, a protease, P57, secreted by Photobacterium sp. A5-7 isolated from marine sediment was characterized. P57 could hydrolyze casein, gelatin and collagen. It showed the highest activity at 40°C and pH 8.0. P57 is a new subtilase, with 63% sequence identity to the closest characterized protease. Mature P57 contains a catalytic domain and an inserted PA domain. The recombinant PA domain from P57 was shown to have collagen-binding ability, and Phe349 and Tyr432 were revealed to be key residues for collagen binding in the PA domain. This study first shows direct evidence that the PA domain of a subtilase can bind substrate, which provides a better understanding of the function of the PA domain of subtilases and bacterial extracellular proteases from marine sediment.